DESCRIPTION: (Applicant's Abstract) Dr. Roy Chuck is an M.D., Ph.D. who obtained his degrees from Columbia University under auspices of the National Institutes of Health's prestigious Medical Scientist Training Program Prior to that he obtained an Engineering Science degree from the University of California al Berkeley. He possesses a unique background that encompasses the fields of laser spectroscopy, biochemistry and ophthalmology. The long term objective of this application is to characterize the spectroscopic properties of the cornea during ultraviolet laser ablation to allow identification of spectral features that ma3 differentiate normal from diseased tissue. Specifically, this will be accomplished by the measurement of laser-induced fluorescence in real-time during 193-nm excimer laser corneal surger3 in various normal and disease states including chemical burns and diabetes. All of the data taken together, besides enhancing our knowledge of the spectral features of the cornea in various disease states of ocular health, may also result in the bioengineering development of an instrument to guide the alteration of excimer laser ablative patterns to achieve more predictable surgical results by using real-time spectroscopic feedback information. Much of the work will be accomplished at the Beckman Laser Institute at the University of California, Irvine which is well equipped to support the in vivo and clinical studies of excimer laser corneal surgery and vision within this research program. The Beckman Laser Institute which is located quite close to the department offices is closely affiliated with the Department of Ophthalmology. Housed within the Beckman Laser Institute is a clinical excimer laser that will be used for this study (VISX Star2). In addition, the Beckman Laser Institute contains a fully equipped vivarium for housing of rabbits, the experimental animal that will be used in these investigations Core histology and ultrastructure facilities are also available within the institute. The UCI Department of Ophthalmology has an active cornea and external disease service. This clinical practice will provide the patients for the clinical studies in the final phase of this research.